/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    NominalAttributeInfo.java
 *    Copyright (C) 2014 University of Waikato, Hamilton, New Zealand
 *
 */
package weka.core;

import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;

/**
 * Stores information for nominal and string attributes.
 */
public class NominalAttributeInfo implements AttributeInfo {

    /** The attribute's values. */
    protected/* @ spec_public @ */ArrayList<Object> m_Values;

    /** Mapping of values to indices. */
    protected Hashtable<Object, Integer> m_Hashtable;

    /**
     * Constructs the info based on argument.
     */
    public NominalAttributeInfo(List<String> attributeValues, String attributeName) {

        if (attributeValues == null) {
            m_Values = new ArrayList<Object>();
            m_Hashtable = new Hashtable<Object, Integer>();
        } else {
            m_Values = new ArrayList<Object>(attributeValues.size());
            m_Hashtable = new Hashtable<Object, Integer>(attributeValues.size());
            for (int i = 0; i < attributeValues.size(); i++) {
                Object store = attributeValues.get(i);
                if (((String) store).length() > Attribute.STRING_COMPRESS_THRESHOLD) {
                    try {
                        store = new SerializedObject(attributeValues.get(i), true);
                    } catch (Exception ex) {
                        System.err.println("Couldn't compress nominal attribute value -" + " storing uncompressed.");
                    }
                }
                if (m_Hashtable.containsKey(store)) {
                    throw new IllegalArgumentException("A nominal attribute (" + attributeName + ") cannot" + " have duplicate labels (" + store + ").");
                }
                m_Values.add(store);
                m_Hashtable.put(store, new Integer(i));
            }
        }
    }
}